Process and apparatus for dredging stone and gravel



Sept. 24, 1923. H. 1.. SHOTWELL 1,729,054

PROCESS AND APPARATUS FOR DREDGING STONE AND GRAVEL Filed Nov. 17, 192'? 5, JJ I j A Z9 J4 49A 27 //Vl A 70/?.

Patented Sept. 24, 1929 PATENT OFFICE HARVEY L. SHOTWELL, 0F BUFFALO, NEW YORK PROCESS AND APPARATUS FOR DREDGING STONE.- ANI) GRAVEL Application filed November 17, 1927. Serial No. 233891.

' This invention relates to improvements in processes for dredging stone and gravel in suction stone and gravel dredges and particularlyto means applied to the suction duct or tube of the dredge for use in supplying stone and gravel of the desired size to the mouth of the suction duct.

For some kinds of construction Work the gravel or stone used must contain not more than acertain percentage of sand or under to the cost of the material, not only because of the cost of these operations, but also since because of the presence of the undesired material, the bulk of the material to be handled is greater than it would be if only the actual material desiredwere handled.

The objects of this invention are to provide a process of dredging stone and gravel in such a manner that most of the undesired material is not taken by the dredge; also to provide means at the end of the suction tube or duct of the dredge which select the material which is pumped by the dredge in such a manner that the undesired material is not taken into the suction tube; also to provide a device of this kind which is adjustable so that the grade of size of material pumped by the dredge may be varied as desired; also to provide a device of this kind inwhich the suction mouth into which the material enters may be supported at different elevations above the bottom of the body of water on which the dredge is operating; also to provide a device of this kind which is so constructed that'it may be dragged over the bottom of the body of water while said dredge is in operation; also to provide a device of this kind which is provided with teeth which dig below the upper surface of the bottom of the body of water and which act to raise material of the kind desired above the upper surface of the bottom; also to provide a device of this kind which will readily adapt itself to operation at different depths of water; also to improve the construction of devices of this kind and process of dredging in other respects hereinafter specified.

In the accompanying drawings,

Fig. 1 is aside elevation of an attachment embodying my invention, which is to be applied to the intake end of the suction tube or duct of. the dredge.

Fig. 2 is a top plan view thereof.

Fig. 3 is a central sectional elevation thereof.

Fig. 4 is a sectional line 44, Fig. 1.

Fig. 5 is a rear elevation thereof.

Fig. 6 is a transverse sectional elevation thereof on line 6 6, Fig. 2.

i Fig. 7 is a fragmentary top plan View thereof on an enlarged scale.

In accordance with my improved process of dredging, the inlet. opening of the suction tube of the dredge faces rearwardly with reference to the direction of movement of the dredge, instead of downwardly into the material which is to be dredged or forwardly with reference to the direction of movement of the dredge, as was heretofore done, and in order to bring the stone or gravel desired into the opening of the suction tube, provision is made for dragging the bottom of the body of water on which the dredge is working, and at the same time raising the stone or gravel desired to the inlet mouth of the suction tube, and in this manner material which is not desired, such,'for example, as sand, small stones, or fiat stones, are not brought into operative relation to the suction opening of the dredge and are therefore not handled by the dredge. My improved process therefore involves the rakplan View thereof on ing of the bottom of the bodyof water and the carrying of the desired stone or gravel upwardly to the suction inlet of the dredge, which faces rearwardly with reference to the direction of movement of the dredge.

'10 represents a metal tube which is suitably connected with and forms a part of the suction duct or tube of a dredge and to which my at- -which the dredge is operating.

tachment is secured. Briefly stated this attachment includes a suction mouth A having a suitable pivoted or swivelled connection with the suction tube 10, and which is preferably arranged substantially parallel to the bottom of the body of water on which the dredge is operating and which has an intake opening at the rear end thereof, and a rake or drag member 13 arranged at the suction opening of the mouth A and arranged in such relation thereto as to bring the desired material to this suction opening, from which it is carried through the mouth and through the tube 10 by the force of the current of water drawn by the dredge through this tube. The

material is dumped by the dredge into a suitable container in which the excess water is allowed to return to the body of water on The suction dredge and parts thereof may be the same as that now commonly used and is therefore not illustrated in the drawings.

The suction mouth A and the rake B together with the parts connected therewith are so connected with the suction tube 10 as to move up and down and also to swing axially with reference to this tube so that the device may adapt itself to use at differentdepths of water and to any unevenness in the bottom of the body of water on which the dredge is working. Any suitable or desired universal connection or connections between the mouth A and the rake B and the tube 10 may be provided. In the particular construction which is illustrated in the drawings by way of example, the tube 10 is connected with a laterally flaring tube 11 by means of a joint which permits axial movement of the flaring tube 11 with reference to the suction tube 10. One end of the flaring tube 11 is cylindrical and approximately of the same diameter as the suction tube 10, and the end of the suction tube 10 and the cylindrical portion 12 of the flaring tube extend within a sleeve 14 provided with rings 15 suitably secured to the inner face thereof. Two of the rings 15 in the construction illustrated-bear against rings 16 secured to the lower end of the suction tube 10 and two other rings15 of the sleeve 14 M tion tube 10. Any other connection between these two tubes may be provided, if desired.

The other end of theflaring tube 11 is flared laterally and reducedin height and is so 0011- nected with'the suction mouth A as to permit this mouth to move up and down relatively to the flaring tube 11. I Any suitable or desired connection between the flaring tube 11 and the suction mouth may be provided for this purpose, that shown in the drawings by way of example being constructed as follows :The laterally flared end of the tube 11 is connected to a transversely extending short tube 20 which has an opening 21 which coincides with the opening in the flaring end of the tube 11. The tube 20 is provided with another opening 22 on the opposite side thereof through which the discharge end of the suction mouth A extends. This end of the suction mouth is secured to a part 24 which is partially cylindricalin form and is arranged concentrically within the tube 20 in such a manner that the cylindrical section 24 may turn concentrically with the tube 20, and thus permit the suction mouth A to move up and down relatively to the flaring tube 11. In order to hold this cylindrical section 24 in concentric relation to the tube 20, a pair of disks 25 are preferably provided at opp0- site sides of the suction mouth A and secured to the cylindrical section 24. These disks are so formed as to substantially fill the interior of the tube 20 and turn with the cylindrical section 24 so that this section is held concentrically with reference to the tube 20, and also the disks prevent the material which is being acted upon by the dredge from entering into the ends of the tube 20. Consequently because of the two joints described, the suction mouth A has a limited up and down movement relatively to the flaring tube 11 and the tube 11 is free to move about the axis of the suction tube 10, so that the suction mouth A has a imiversal connection with the suction tube 11 within certain limits. Any other connection between the suction mouth A and the flaring tube 11 may be provided or if desired any other type of universal joint or connection between the suction tube 10 and the suction mouth A may be provided, if desired.

The suction mouth A is substantially rectangular in cross section, and the receiving opening of this mouth is preferably provided with bars or grids 27 extending crosswise thereof so as to prevent the entrance into the suction mouth of any stones or other material which might not be able to pass through the cylindrical end of the flaring tube 11. If desired, a larger or smaller number of these grids 27 may be employed to control the size of stone which is taken in through the inlet opening in the, suction mouthA; The upper wall 28 of the suction mouth extends rearwardly to a greater extent than the lower wall 29 and may if desired be curved or rounded at the rear end thereof to conform with the shape of the rake or drag member and to ensure the entrance of stone or gravel into the intake opening of the suction mouth. The rake or drag'B which carries the stone or gravel into operative relation to the inlet 1 on and extendin downwardl therefrom,

about the receiving end of the suction mouth A. The rake teeth are preferably removably secured on the bail 30 so that they can be replaced if worn or damaged. For example the upper ends of the rake teeth may be reduced in diameter and threaded. These threaded ends extend through holes in the bail 30 and are held in place by nuts 33. By arranging the rake teeth in an arc of a circle about the intake end of the suction mouth, the rake or drag tends to deliver stone from opposite sides of the inlet opening into operative relation to this inlet. The bail member 30 may consequently be made wider, if desired, to cover a greater area during its movement.

The member 30 is pivoted at 32 on a main frame member 34 of the drag or rake which is suitably mounted in operative relation to the suction mouth A of the device. This frame member may be of any suitable shape, that shown having arms 35 extending forwardly therefrom and provided at their front ends with means for releasably and adjustably attaching the frame to rings or bearings 36 which extend around the tube 20 and are journalled to swing about the tube. The rear end of the frame member is preferably rounded to correspond. approximately to the curvature of the bail 30. The front ends of the rings 36 are preferably provided with eyes or loops 3'? to which two ends of a chain or bridle 38 are attached by means of which the rake or drag and the suction mouth may be dragged over the bottom of the body of water by means of the dredge or other propelling means. The frame member 34 cooperates with the rake teeth 31 to support the lower portions thereof in any suitable or desired manner, the frame member shown being provided with a series of holes through which the rake teeth 31 pass. The rear end of the frame member 34 is preferably flat and of considerable width and adapted to slide over the bottom of the body of water ori which the dredge is working.

The adjustable connection between the arms 35 and the rings 3-6 may be of any suitable kind, for example the rings 36 may be provided with rearwardly extending brackets or parts 39 provided with holes for bolts 39 which are adapted to pass through any one of a plurality of holes 39 in the arms 35. By means of this arrangement the drag or rake member B may be readily detached for repairing or for replacing the same by another drag or rake having differently spaced rake teeth to enable the device to operate on stone or gravel of different sizes, or the rake member may be spaced so that the teeth thereof are located at different distances beyond the rear end of the suction mouth, as may be necessary when operating under different conditions or to dredge material of different size.

In order to support the rake teeth 31 in different relations to the frame member 34 of.

the device, an adjustable connection is provided between the frame member 34 and the bail 30. This connection may be in the form of a slotted member or link 40 pivotally connected at its lower end to the frame member 34, and connected with the bail 30 by means of a bolt 41 pivotally mounted on lugs 42, a nut 43 cooperating with the bolt serving to clamp the adjusting link 40 against the bail 30. Any other adjustable connection between the bail 30 and the frame member 34 may be provided, if desired. By means of this connection the distance to which the rake teeth 31 extend below the frame member 34 may be varied, as maybe seen by reference to Figs. 1 and 3, the teeth being set in Fig. 1 in such a manner as to cause them to dig deeper into the bottom of the body of water than in the arrangement shown in Fig. 3. Since the frame member 34 normally moves over the upper surface of the bottom of the body of water, the distance to which the rake teeth penetrate the bottom can be regulated by varying the adjustment of the bail 30 with reference to the frame 34. The frame memher also reinforces the rake teeth and relieves the bail 30 of most of the strains resulting from dragging the device over the bottom.

Means are preferably also provided for supporting the suction mouth A in different relations with reference to the bottom of a. body of water, and, in the particular construction shown, an arm 45 is pivoted at 46 at each side of the suction mouth A, and the end of this arm 45 is provided with an upwardly ex tending are shaped portion 47, provided with apertures 48 through which a bolt 49 may extend. This bolt also extends through a hole in the side of the suction mouth A. These arms form skids,thelower surfaces of which are dragged across the bottom of the body of water and the arms 47 of which hold the suction mouth A at different elevations with reference to the bottom. The arms are shown in two extreme positions which they may occupy in Figs. 1 and 3. Other means for holding the discharge end of the suction mouth at different elevations above the surface over which the device travels may be employed, if desired.

The ends of the transverse tube or pipe 20 are preferably closed in any suitable manner, for example, by means of caps 50 suitably secured to the ends of the pipe, and if desired eye bolts 51 may pass through apertures extending through the flanges of the caps and the pipe 20 and these eye bolts may be connected by brace rods or links 52to suitable eyes 53 formed on a ring 54 rigidly secured on the cylindrical portion 12 of the flared tube 11 for the purpose of reinforcing the connection between thefla-red tube and thetransverse pipe or tube 20. 7

Means may also be provided for preventing the suction mouth A from swinging out of operative relation to the frame 34 ofthe device, and for this purpose, in the construction illustrated, a chain 57 is provided, one end of which is connected to an eye 58 secured to the suction mouth A and theother end may be secured at 59 to the bail 30. Other means may be provided for this purpose, if desired.

In the operation of the device it is understood, of course, that the same is secured to the end of the suction tube of a dredge and lowered to the bottom of the body of water on which the dredge is working. The pumps of the dredge are then started to draw water through the suction pipe 10 and the suction mouth A, and the device is dragged along the bottom of the body of water through the medium of the chains 38, this movement being preferably slow. The rake teeth 31 collect the stone and leave the more finely divided matter behind. Most of the flat stones will also pass edgewise between the rake tee 11 33a and the desired stone or gravel will be gathered at the inlet opening of the suction mouth A and will be carried by the rush of water through the suction pipe 10. The various adjustments of the parts of the device depend upon the kind of stone desired and upon the nature of the bottom of the body of water which is being worked on. \Vhen it is desired that the rake teeth should not extend deeply below the top surface of the bottom of the body of water, the teeth may be set with reference to the frame member 3t as indicated in Fig. 3. \Vhen there is comparatively little finely divided matter in the material over which the drag passes, the receiving end of the suction mouth A may be lowered as indicated in Fig. 3. On the other hand when it is desired that the teeth dig deeper into the bottom of the body of water, the-y may be adjusted as shown in Fig. 1 and when there is much finely divided material present in the bottom of the body of water, the receiving end of the suction device may be elevated as shown in Fig. 1 so that only stone which has been piled up in front of the rake teeth up to the level of the intake opening in the suction mouth will be carried upwardly to the dredge. Numerous other adjustments of the parts may be effected to obtain the desired results.

The process and construction described has the advantage that the dredge only draws up the particular kind of materialwhich is desired, while other or undesirable material such as finely divided material and flat stones are not gathered together at the receiving end of the suction month by the rake teeth, and are consequently not elevated by the dredge. Consequently further grading or Washing of the material taken bythe dredge is not necessary,'and the total bulk ofmaterialhandled by the dredge is reduced. If it is desired to adjust theapparatus for use in connection with larger stones, alternate teeth 31 may be removed so that stones smaller than the spaces between the rake teeth will not be fed by the teeth toward the receiving end of the suction mouth A.

Claims 1. A process for dredging stone and gravel consisting of raking the bottom of a body of water by a continuous movement in a forward direction to gather stone and gravel while leaving finer material behind, and drawing the stone and gravel thus raked toget-her upwardly by a stream of water produced by suction.

2. A process for dredging stone and gravel consisting of dragging a suction member over the bottom of a body of water with the suction intake opening facing rearwardly with reference to the direction of movement, and raking together stone and gravel by a continuous movement in a forward direction into proximity to said intake opening of the suction device to cause said stone and gravel to be carried by a current of water produced by suction while finer material is left behind.

3. A process for dredging stone and gravel consisting of dragging a suction member over the bottom of a body of water,gathering together stone and gravel on the bottom of said body of water and separating the same from finer material by a continuous raking movement in a forward direction and drawing the stone and gravel thus gathered into said suction member by a current of water.

4. A process for dredging stone and gravel consisting of drawing a suction tube over the bottom of a body of water with the intake opening thereof facing rearwardly and arranged above the surface of said bottom, and raking said bottom by the movement of said suction tube to cause stone and gravel to be drawn above said bottom into a position to be received by said intake opening of said suction tube while leaving finer material behind.

5. A process for dredging stone and gravel consisting of drawing a suction tube over the bottom of a body of water with the intake opening thereof facing rearwardly and arranged above the surface of said bottom,

raking said bottom immediately about said intake opening by the movement of said suction tube to cause stone and-gravel to be drawn above said bottom into a position to be re ceived by said intake opening of said suction tube, while finer material is left behind and varying the elevation of said suction intake opening above the surface of the bottom of the body of water to vary'the material drawn into said suction inlet.

' 6. A process for dredging stone and gravel consisting of dragging a suction member over the bottom of a body of water with the suction intake opening facing rearwardly with reference to the direction of movement, raking together stone and gravel into proximity to said intake opening of the suction device by the movement of said suction tube to cause said stone and gravel to be carried by a current of water produced by suction, while finer material is left behind and varying the relative position of the intake opening with reference to the raking means to vary the grade of material drawn into said intake opening.

7. A device for collecting stone and gravel including a suction passage arranged substantially parallel to the surface which is being worked on and having an opening at the rear thereof, and a rake arranged in rear of the intake end of said suction tube and adapted to carry stone or gravel of the desired size toward said intake end of said tube while leaving material of smaller size behind.

8. A stone or gravel gathering device for use in connection with a suction dredge, including a suction tube having an elongated inlet opening, and a series of teeth arranged in operative relation to said inlet opening so that said teeth when dragged over the bottom of a body of water carry stone of the desired size to said inlet opening while permitting smaller material to pass between said teeth.

9. A device adapted to be attached o a suction duct of a dredge and adapted to operate on the bottom of a body of water, in-

eluding a suction passage open at its rear end, and a drag including teeth adapted to rake the bottom of the body of water and said teeth being spaced apart at such distances that material of a smaller size than that desired passes between said rake teeth, while stone and gravel of the desired size is carried to said open end of said duct.

10. A device adapted to be attached to a suction duct of a dredge and adapted to operate on the bottom of a body of water, includin a suction passage open at its rear end, a drag including teeth adapted to rake the bottom of the body of water and spaced apart to carry stone and gravel of the desired size to said open end of said duct while leaving finer material behind, and means connected to said drag for moving the same on the surface of the bottom of the body of water.

11. A device adapted to be attached to a suction duct of a dredge and adapted to operate on the bottom of a body of water, including a suction passage, a suction mouth connected with said suction passage and having an intake opening in the rear end thereof, and a toothed rake arranged in rear of said opening for raking stone and gravel toward said opening while permitting finer material to pass between the rake teeth and adjustable toward and from said intake openmg.

12. A device adapted to be attached to a suction duct of a dredge and adapted to operate on the bottom of a body of water, including a suction passage, a suction mouth having a swivelled connection with said suction passage and having an intake opening in suction duct of a dredge and adapted to operate on the bottom of a body of water, including a suction passage, a suction mouth having a swivelled connection with said suction passage .and havin an intake opening in the rear end thereo means for supporting said suction mouth at different elevations above thebottom of a body of water, a rake arranged in rear of said opening for raking stone and gravel toward said opening, and means for adjusting said rake toward and fromsaid opening.

. 14. A device adapted to be attached to a suction duct of a dredge and including a 1 suction mouth and a rake operatively connected and adapted to be dragged over the bottom of a body ofwater to enable the rake to gather stone and gravel into a position to be taken into said suction mouth while smaller material passes through the rake and is nottaken in by said suction mouth.

15. A device adapted to be attached to a suction duct of a dredge and including a. suction mouth pivoted to swing axially about I;

said suction duct and to swing vertically with reference to said suction duct and having an intake opening at the rear end thereof, and a rake connected with said suction duct and extending to the rear thereof and adapted to 16. A device adapted to be attached to a-- suction duct of a dredge and including a suction mouth having, a swivelled connection 'with said suction duct to swing about the axis of said duct and also to move vertically,

said suction mouth being flared out laterally and having an intake opening at the rear end thereof, and a rake member pivotally connected with said suction mouth to swing vertically relatively to the same and having teeth for raking stone and gravel into operative relation to said intake opening, finely divided matter passing between said teeth.

17 A device adapted to be attached to a suction duct of a dredge and including a sucw on tion mouth having a swivelled connection;,,130

with said suction duct to swing about the axis of said duct and also to move vertically, said suction mouth being flared out laterally and having an intake opening at the rear end thereof, a rake member pivotally mounted on said suction mouth to move vertically relatively to the same and extending into operative relation to said intake opening to move stone and gravel into operative relation to 10 said inlet, and means for adjusting said rake and suction mouth relatively to each other to vary the size of stone taken in through said suction mouth. A

18. A device adapted to be attached to a suction duct of a dredge and including a suction passage operatively connected with said suction duct and having an intake at the rear end thereof, and a rake member pivotally connected with the suction mouth and including rake teeth extending into operative relation to the intake of said suction mouth to carry stone and gravel into operative relation thereto, and means for controlling the extent to which said rake teeth penetrate below the surface of the bottom of the body of water on Y which the dredge is operating.

19. A device adapted to be attached to a suction duct of a dredge and including a suction passage operatively connected with said suction duct and having an intake at the rear end thereof, and a rake including a frame member pivotally mounted with reference to said suction mouth and extending in rear of the intake of said suction mouth, and rake teeth adjustably arranged with reference to said frame, and means for adjusting said rake teeth to extend to different distances below said frame to control the extent to which said rake teeth penetrate the bottom of a body of water on which the dredge is working, to raise stone and gravel of a size which cannot pass between the rake teeth into operative relation to the suctioninlet passage in said suction mouth;

20. A device adapted to be attached to a suction duct of a dredge and including a suction passage operatively connected with said suction duct and having an intake at the rear end thereof, a rake including a frame member pivotally mounted with reference to said suction mouth and extending in rear of the intake of said suction mouth, rake teeth adjustable with reference to said frame to vary the extent to which said teeth may extend below said suction duct to raise stone and gravel, of a size which cannot pass between the rake teeth, into operative relation to said intake, and means for adjusting said intake to different elevations relative to the bottom of a body ofv water on which the dredge is working.

HARVEY L. SHOTWELL. 

